Variations of age or developmental stage could influence plants’ ability for drought resistance.Ten drought-resistance physiological characteristics of Juniperus sabina at three ages were measured in this paper.Results indicated that:(1)The values of water-losing rate were already significantly different among different seedling ages under the condition of normal water supply,so were relative permeability of membrane and RuBP activity.But there was no significantly difference on relative water deficiencies (RWD),stomatal conductance(G_s),net photosynthesis (P_n) rate etc.among these three seedling ages.(2)Under water stress,there was still no significant difference on RWD and G_s among these three seedling ages all along.The P_n,transpiration rate(T_r),water use efficiency (WUE)and intercellular carbon dioxide concentration (C_i) of these three seeding ages were significantly different when the SWC is 6.78%.As the SWC got down to 4.52%,significant difference appears among these three ages on their light-use efficiency.(3)Comparison of these three age-groups showed that P_n,RuBP activity and light-use efficiency of the 5-year old seedlings were significantly lower than that of the 1-year old seedlings’ under water stress.Nevertheless,C_i,magnitude of the declines in G_s and T_r,and magnitude of the increase in WUE of the 5-year old seedlings were significantly higher than that of the 1 and 3-year old seedlings’.Thus it can be seen that seedlings’ responses to drought stress may differ between different seeding ages.The stability of the drought-resistance indicators to age were different.The 1-year old seedlings have more life vitality than 5-year old seedlings and the 5-year old seedlings were much more adaptable to water stress.We should better choose the materials at the same age during drought resistance appraisal ,and the sensitivity and stability of indicators to seedlings’ age must be considered.